(lambda spectrogram (fullpath)
  (var spawn (. (require "child_process" spawn-sync)))
  (var read  (. (require "fs") read-file-sync))
  (var output (+ fullpath ".png"))
  (spawn "sox" (array
    fullpath
    "-n" "spectrogram"
    "-r" "-a"
    "-x" 1024 "-y" 96
    "-o" output))
  (return (fs.read-file-sync output)))
